Cathode-ray tube display device

ABSTRACT

A cathode-ray tube (CRT) display device for alphanumeric characters includes a first boundary register for storing the numerical value of a boundary defining the beginning of a row line of characters to be displayed on the CRT. A second boundary register stores a numerical value representing the end of the row line. A first position control counter designates the position of a character in the row line direction. A boundary detector compares the numerical value of the second boundary register with the numerical value of the first position control counter. When the result of the comparison shows that the first position control counter value is larger than the second boundary register, a check pulse is initiated which is employed to reset the counters and initiate a new line of characters on the CRT.

United States Patent 3,453,384 7/1969 Donner etal inventors Appl. No.

Filed Patented Assignee Priority pan 4262568 CATHODE/RAY TUBE DISPLAYDEVICE 1 Claim, 5 Drawing Figs.

US. Cl 340/324A, 95/45 Int. Cl. 606 3/14 Field ofSearch 340/324.l;95/45; 178/66, 6.7, 15, 89, 90

References Cited UNITED STATES PATENTS CflMPUTER Primary ExaminerJohn W.Caldwell Assistant Examiner-David L. Trafton Att0rney-H0pg00d andCalimafde ABSTRACT: A cathode ray tube (CRT) display device foralphanumeric characters includes a first boundary register for storingthe numerical value of a boundary defining the beginning of a row lineof characters to be displayed on the CRT. A second boundary registerstores a numerical value representing the end of the row line. A firstposition control counter designates the position of a character in therow line direction. A boundary detector compares the numerical value ofthe second boundary register with the numerical value of the firstposition control counter. When the result of the comparison shows thatthe first position control counter value is larger than the secondboundary register, a check pulse is initiated which is employed to resetthe counters and initiate a /3 24A new line of characters on the CRT I!30,1, 4 503 20/ i 407 mil e 4 aim/2'4 CIRCUIT DECODER GENE/Mme /0/ d,402 4. Y-Pos/r/ou I we; 403 40 v/' X-Pn/r/zw 402 zzzz'i z, 406 70 L Jon/veer Boo/many '0/V7H0l. 'IPCU/f 7 CATHODE/RAY TUBE DISPLAY DEVICEBACKGROUND OF THE INVENTION The present invention relates to a cathoderay tube (CRT) display device which automatically renders a uniformformat to a group of characters appearing on the display face of acathode ray tube.

In the conventional CRT display device for converting informationsignals derived from an infonnation processor, such as an electroniccomputer, into a visible pattern, both the size of the characters to bedisplayed and the position of the characters on the display face arepredetermined. Consequently, in order to make the format uniform, it hasbeen sufficient to designate, via an instruction information of thecomputer, the number of characters to be displayed in one row line.Where, however, the characters to be displayed comprise several sizes,it has heretofore been impossible for such a CRT display device todisplay the characters.

, A recently developed CRT display device is capable of designating acoordinate point (X0, Y), in response to the instruction information ofthe computer, for the first character of a character group. The CRTdisplay face is assumed to be a coordinate plane. For this CRT displaydevice to automatically sequence horizontally or vertically from theinitial position and display various sizes of characters, it isnecessary for the computer instruction code to designate in advance thenumber of characters to be displayed along with the size and the format.However, it will be appreciated that the designation of such informationof the computer is extremely complicated.

For example, where several widths of characters with uniform height areemployed, taking into consideration the quality of characters to bedisplayed, a matrix of 5X7 (a character is displayed by a combination ofbright or dark spots at 5X7 dot points) is generally used when romanletters and numerals are displayed with dot patterns. However, thespecific roman letter I may be displayed with a matrix of 3X7, while theletter W would require a matrix of 7X7. With uniform height charactersof varying widths, it has thus been difficult for such CRT displaydevices to display the character even when they are displayed at auniform spacing between adjacent characters.

OBJECT OF THE INVENTION It is the object of the present invention toprovide a CRT display device capable of automatically restoring theinitial display state and making a new row line upon the displayreaching the end of the predetermined display region, regardless of thenumber of characters to be displayed in a row line or the size and kindof characters to be used.

SUMMARY OF THE INVENTION The present invention provides a CRT displaydevice comprising a first boundary register for storing a numericalvalue of a boundary defining the beginning of a row line of characterson the CRT display face; a second boundary register for storing anumerical value representative of the end of the row line; a firstposition control counter for designating a position of character in therow line direction; a second position control counter for designatingthe character position in the column line direction; and a boundarydetector.

The boundary detector compares the output numerical value of the secondboundary register with the output numerical value of the first positioncontrol counter. When the result of the comparison shows that the outputnumerical value of the first position control counter is larger thanthat of the second boundary register, a boundary check or detectionpulse from a command decoder is caused to pass through the boundarydetector, and changes the contents of the position control counter tothat of the boundary register indicating the boundary of the beginningof the row line of characters. Also,

character in the column direction, to be changed to a constant valuedesignated according to the height of the character. Thus, the resettingand initiation of a new line are carried out by changing the contents ofthe first and second control counters.

According to the present invention, therefore, if the positions of thefirst and last characters among a character group are once designated,each character is displayed one by one on the display face, and when thedisplay has reached the predetermined position near the end of a rowline, the resetting is automatically carried out, thus enabling adocument to be displayed in good format.

The above-mentioned and other features and objects of this invention andthe manner of attaining them will become more apparent and the inventionitself will best be understood by references to the followingdescription of an embodiment of the invention taken in conjunction withthe accompanying drawings, the description of which follows:

FIG. 1A shows a block diagram of a cathode ray tube display device ofthe present invention;

FIG. 1B shows a block diagram of the control section of the presentinvention;

FIG. 2 shows various sizes of characters which may be indicated on thedisplay face of the cathode ray tube display device; and

FIGS. 3A and 3B show the timing relationship between X- directioncounter output, Y-direction counter output, and intensity controlsignals for the letter A indicated by I and II in FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS In FIG. 1A, a computer is employedas an information processor 1, and the display information from theinformation processor 1 is stored in the form of a command signal in amemory 3 via a control circuit 2. The information signals to be storedin the memory 3 include, for example: a positioning command informationdesignating the position of the first dot of a character to be displayedon the display face of the cathode ray tube 8; the numerical informationdefining coordinates (X, Y) of said position on the display face; acharacter designation command information indicating that the characterto be displayed is a letter; and coded information of a character to bedisplayed, all arranged in the order mentioned above.

The control circuit 2, for controlling the above-described informationsignals, comprises a circuit for interconnecting the informationprocessor 1 and the memory 3, and includes conventional means forreading out information from the memory 3 and sending the readoutinformation to a command decoder 4, a sequence control counter fordesignating an address in the memory 3 at the time of readout andwrite-in, and a timing pulse generator for controlling theabove-described operations. The command decoder 4 decodes the commandinfonnation signals read out from the memory 3 and distributes thelast-mentioned numerical information signals and coded informationsignals of characters following each command information signal, toposition control circuit 6 and a character generator 5, respectively.The character generator 5 receives coded information signals ofcharacters from the command decoder 4, and produces intensity-modulatingand program pulses for scanning X and Y directions to be supplied tosignals corresponding to a visible pattern, the cathode ray tube 8, andthe position control circuit 6, respectively. The position controlcircuit 6 comprises a X position control counter 61 and a Y positioncontrol counter 62, each of which respectively stores the positioninginformation supplied from the command decoder 4 in the form of X and Ycoordinates of the position of the first dot forming a character to bedisplayed at first on the CRT display face. A boundary control circuit 7comprises (as shown in FIG. 1B), in the case of characters beingarranged in .a horizontal scan display, a left-end boundary register 72for defining the beginning of the display region of characters row, aright-end boundary register 73 for defining the end of the characterrow, and a boundary detector 71 for comparing the contents of theabove-described X position control counter 61 with the contents of theabove-described right-end boundary register 73.

The cathode ray tube unit comprises the cathode ray tube 8, a X-axisdeflecting coil 11 for deflecting the electron beam in the X(horizontal) direction, and a Y-axis deflecting coil 14 for deflectingthe electron beam in the Y (vertical) direction. Digital-Analogue (D/A)converters 9 and 12 are for converting signals from the position controlcircuit 6 into analogue signals to be supplied to the X-axis and Y-axisdeflecting coils of the CRT unit.

In operation,'an information in the form of the command form theinformation processor 1 is stored in the memory 3 via leads 101 and 201.This operation is carried out according to a location address designatedby the sequence control counter in the control circuit 2. Theinformation stored in the memory 3 is transmitted under the command ofthe location address sent from the control circuit 2 through a lead 202to the command decoder 4 via leads 301 and 203. In the command decoder4, the information signals are decoded into the character informationsignals to be supplied to the character generator 5 and the numericalinformation signals to be supplied to the position control circuit 6,respectively. The position control circuit 6 designates, in response tothe numerical information, a position of the first dot forming acharacter to be displayed at first on the display face of the CRT 8. Onthe other hand, the character information applied to the charactergenerator 5 causes the generator 5 to produce the intensitymodulatingsignals representative of the pattern to be displayed, and programpulses representative of the scanned X and Y coordinates. Theseintensity-modulating signals and program pulses are applied to the CRT 8and the position control circuit 6, respectively.

Referring to FIG. 1B, which shows an essential part of the embodiment,the X position control counter 61 receives the X coordinate programpulse, a character size designating information, a X-positioninginformation, a boundary detection pulse and a left-end output numericalvalue, through an input lead 501, an input lead 505, an input lead 401,an input lead 702 and an input lead 703, respectively. An output lead611 of the counter 61 is connected to the boundary detector 71 and theD/A converter 9. The Y position control counter 62 is connected by aninput lead 502 to the character generator 5 for receiving the Ycoordinate program pulse. Through another input lead 402, the counter 62receives a Y-positioning information. Similarly, through the input lead505 and the input lead 702, the counter 62 receives the character sizeinfonnation and the boundary detection pulse, respectively. The outputlead 621 of the counter 62 is connected to the D/A converter 12.

The left-end boundary register 72 receives, through an input lead 403,the numerical value indicating the left-hand end position of a row line.The output lead 703 of the register 72 is connected to the X positioncontrol counter 61. Through an input lead 404, the right-end boundaryregister 73 receives the numerical value indicating the right-hand endposition of a row line of characters. An output lead 704 of the register73 is connected to the boundary detector 71. The detector 71 receivesthe output of the counter 61 and the numerical value indicating theright-hand end position of a row line of characters through the inputleads 611 and 704, respectively. The detector 71 receives, via lead 405,a comparison command signal which causes the detector 71 to compare theoutput of the counter 61 with right-hand end defining output of theright-end boundary register 73. Also, the detector 71 receives aboundary check pulse through an input lead 406. The character generator5 is connected by a lead 701 and the lead 702 to the boundary detector71 for receiving a boundary nondetection pulse and the boundarydetection pulse, respectively.

Boundary designation signals designating the region of characters to bedisplayed on the display face of the CRT display device are stored inadvance in the left-end boundary register 72 and the right-end boundaryregister 73 through the leads 403 and 404. in addition, the boundarydetector 71 receives the boundary check pulse through the lead 406. Thecomparison command signal which brings the detector 71 into the state ofcomparing the output of the position control counter 61 with the outputof the boundary register 73 is received through the lead 405.

The information received from the information processor 1 and stored inthe memory 3 is read out through a lead 301 in response to the locationaddress sent from the control circuit 2 through the lead 202, and istransmitted to the command decoder 4 through a lead 203.

Upon receipt of the positioning command information first, the commanderdecoder 4 supplies, through the leads 401 and 402, positioninginformation signals to the X position control counter 61 and Y positioncontrol counter 62, The command decoder 4 then sends the end pulse tothe control circuit 2 through a lead 408. The control circuit 2 controlsthe memory 3 so as to read out the command information of the followinglocation. On the other hand, the numerical value set in the counter 61is compared with the numerical value set in the right-hand boundaryregister 73 by the boundary detector 71 when the signal supplied throughthe lead 405 and the boundary check pulse supplied through the lead 406are applied to the boundary detector 71. The boundary detector 71 isready to send out the boundary check pulse to the lead 701 as a boundarynondetection pulse indicating that the signal value of the X positioncontrol counter 61 is smaller than that of the signal X of the right-endboundary register 73.

The command decoder 4 decodes the character designating commandinformation and the coded information of character and transmits them tothe character generator 5 through a lead 407 and transmits the boundarycheck pulse to the boundary detector 71 through the lead 406. When thecharacter generator 5 receives the boundary nondetection pulse from theboundary detector 71, it generates the program pulses of X and Ycoordinates to change the contents of the control counters 61 and 62through leads 501 and 502. Also, the contents of the counters 61 and 62are sent out respectively as output signals to the D/A converters 9 and12 through the leads 611 and 621 in synchronism with the scanning of theintensity control matrix. D/A-converted signals drive the X-axis andY-axis deflection coils 11 and 14 through leads 10 and 13 to deflect theelectron beam in X and Y directions.

The intensity-modulating signals representative of display pattern sentout from the character generator 5 are supplied to the CRT 8 through alead 503. Thus, the patterns of characters are displayed at positions ofthe CRT display face defined by the X-axis and Y-axis deflections.

Upon completion of the display of one total character, the X-directionalprogram pulse changes the contents of the counter 61 by the width of onecharacter plus the interval between horizontally adjacent characters,while the Y- directional program pulse maintains the contents of the Yposition control counter 62 at the Y coordinate value unchanged. As soonas the display of one whole character is completed, the charactergenerator 5 transmits a onecharacter-display-end pulse to the controlcircuit 2 through a lead 504. The control circuit 2 then causes areadout from the memory 3 of the succeeding coded character informationwith reference to the location address. The read out information istransmitted to the command decoder 4. In such a manner, the charactersare displayed one by one in the horizontal direction on the CRT displaysurface.

The timing relationship between the output signals of the first positioncontrol counter controlled by the X-direction program pulse, the outputsignals of the second position control counter controlled by theY-direction program pulse, and the intensity control signals for theletter A in a 5X7 dot matrix (indicated by arrow l in FIG. 2) and theletter A (indicated by arrow ll in the same drawing) of the first rowline is shown in FIG. 3A and FIG. 3B. When the right-hand end portion isreached after a series of characters or, in other words, when the signalof the counter 61 becomes equal to or larger than the signal X of theright-end boundary register 73, the boundary check pulse is applied asthe boundary detection pulse to the counters 61 and 62 through the lead702. At this time, the input signal applied from the boundary register72 through the lead 703 is applied to the position control counter 61.This boundary detection pulse and the signal from the boundary register72 change the contents of the counter 61 to the signal X, which is thecontents of the left-end boundary register 72. The boundary detectionpulse also changes the contents of the counter 62 by the appropriatevalue, depending on character height, making a new line. The valuerequired for making a new line is a value corresponding to the sum ofthe height of a character itself and the vertical spacing between eachadjacent character determined by a signal which specifies the size ofcharacters to be displayed.

Subsequent to the foregoing, the character generator 5 is triggered bythe boundary detection pulse supplied through the lead 702 and convertsthe coded information of character stored within itself into anintensity-modulating signal, and applies the X- and Y-directionalprogram pulses to the position control circuit 6.

Further operation is similar to the first line scanning mentioned above.When the size of characters to be displayed is changed, the charactergenerator 5 generates a signal representing the character size to thecounters 61 and 62 through the lead 505 to change the input digitpositions of the program pulses to be applied to the counters 61 and 62.Then, the contents of these counters are changed by the program pulseshaving a scanning unit corresponding to the size of characters.

In FIG. 2, X indicates the horizontal direction and Y indicates thevertical direction of the CRT display surface. X, indicates thedisplay-initiation position (Left-end boundary) and X thedisplay-completion position (right-end boundary). ln addition, Y,indicates the initial position of the roman letters A in the first rowline. When roman letters are displayed horizontally in the displayregion between X, and X,, the number of letters to be displayed dependson the size and kind of characters. For example, the first row line'shows that capital letter A is repeatedly displayed in large size andwith horizontal spacing of four lattice points. The second line showsthat the smaller sized capital letter A is also repeatedly displayedwith the spacing of two lattice points. As is seen from the drawing,even in the case of display of the uniformsized letters, it is evidentthat the number of letters displayed in one row line is different. Todemonstrate this, letter I of 3X7 matrix and letter W of 7X7 matrix areshown in the third and fourth lines in FIG. 2.

Points Z displayed at the right-hand end of the last letter in each linehave the same respective uniform spacing from the last letter andindicate the point at which a new line should be started. In each ofthese cases, however, the position control circuit 6 is controlled sothat the succeeding letter is displayed on the first position of thenext new row line.

It will be obvious to those skilled in the art that the above embodimentis applicable to the vertical scanning display with slight modification.

While the principles of the invention have been described in connectionwith specific apparatus, it is to be clearly understood that thisdescription is made only by way of example and not as a limitation tothe scope of the invention as set forth in the object thereof and in theaccompanying claims.

What we claim is:

1. In a cathode ray tube display device of the type for seriallydisplaying the output of a data processor on a cathode ray tube andincluding means for converting said output into a sequence of languagecharacters, the improvement coupled to said convertin means comprising:

a first boundary register for storing a numerical value of a coordinateposition on the cathode ray tube defining the beginning of a row line ofcharacters;

a second boundary register for storing a numerical coordinate positionrepresentative of the end of the row line;

a position control counter for designating the coordinate position ofthe character being displayed on the cathode ray tube in the row linedirection;

a boundary detector coupled to said position control counter and saidsecond boundary register for comparing the coordinate valuestherebetween and initiating a signal upon an indication that the valuein the position control counter is larger than the second boundaryregister; and

means responsive to said signal to initiate the beginning of a new lineof characters on the cathode ray tube face at said first boundary and ata new vertical coordinate position.

1. In a cathode ray tube display device of the type for seriallydisplaying the output of a data processor on a cathode ray tube andincluding means for converting said output into a sequence of languagecharacters, the improvement coupled to said converting means comprising:a first boundary register for storing a numerical value of a coordinateposition on the cathode ray tube defining the beginning of a row line ofcharacters; a second boundary register for storing a numericalcoordinate position representative of the end of the row line; aposition control counter for designating the coordinate position of thecharacter being displayed on the cathode ray tube in the row linedirection; a boundary detector coupled to said position control counterand said second boundary register for comparing the coordinate valuestherebetween and initiating a signal upon an indication that the valuein the position control counter is larger than the second boundaryregister; and means responsive to said signal to initiate the beginningof a new line of characters on the cathode ray tube face at said firstboundary and at a new vertical coordinate position.